We carry the largest range of crimping sleeves on the planet; copper, aluminium, round, oval and double barrel. We have sleeves for every fishing requirement. It's important to use only copper sleeves on cable leaders to reduce electrolytic corrosion in salt water. For mono leaders use either alloy or copper sleeves. Remember, always use the correct size sleeve for the job, and always use the correct crimping tool. Regular pliers will crush mono, weakening it severely.